Feature: Add unshorten.me API key

[sm4rk0]

Hi and thank you for this helpful app!

I'd like to suggest adding the possibility to add our own unshorten.me API key because it looks like unshorten.me doesn't allow anonymous requests anymore:

curl https://unshorten.me/json/https://bit.ly/asd
{
    "requested_url": "https://bit.ly/asd",
    "success": false,
    "resolved_url": "",
    "error": "Authentication Error"
}

Thanks in advance!

[sm4rk0]

...another issue, on the unshorten.me side is that you can't register at the moment because you get Error 500 on submitting the signup form.

[TrianguloY]

Yup, it's currently broken, which is not good.

I'll also try to test other providers as suggested here #160 (comment)

[c24w]

Does a third party service provide more functionality than making a request directly to the URL and reading the Location response header?

Edit: I think I see the difference. Only HTTP redirects which are masking the real destination should be unwrapped; others, like redirects to a log in page, shouldn't. Still, it could be a simpler option.

[itssoap]

Adding to the comment made by @/c24w, I use the Check Status button in the "Status code" module. If they are not resolved by this:

1. 

A simple location grab from curl will work

2. For complex shorteners which have ads enabled and requires multiple clicks (ex. adf.ly, ouo.io), FastForward extension works pretty well:

https://fastforward.team/bypass-checker

But I don't think their database is public